From b85d18f3bdedca7ae7f2c26ff64ce38c2796bd63 Mon Sep 17 00:00:00 2001
From: Dongjoon Hyun <dongjoon@apache.org>
Date: Thu, 2 Jun 2016 11:12:17 -0500
Subject: [PATCH] [SPARK-15709][SQL] Prevent `freqItems` from raising
`UnsupportedOperationException: empty.min`
## What changes were proposed in this pull request?
Currently, `freqItems` raises `UnsupportedOperationException` on `empty.min` usually when its `support` argument is high.
```scala
scala> spark.createDataset(Seq(1, 2, 2, 3, 3, 3)).stat.freqItems(Seq("value"), 2)
16/06/01 11:11:38 ERROR Executor: Exception in task 5.0 in stage 0.0 (TID 5)
java.lang.UnsupportedOperationException: empty.min
...
```
Also, the parameter checking message is wrong.
```
require(support >= 1e-4, s"support ($support) must be greater than 1e-4.")
```
This PR changes the logic to handle the `empty` case and also improves parameter checking.
## How was this patch tested?
Pass the Jenkins tests (with a new testcase).
Author: Dongjoon Hyun <dongjoon@apache.org>
Closes #13449 from dongjoon-hyun/SPARK-15709.
---
.../spark/sql/execution/stat/FrequentItems.scala | 4 ++--
.../org/apache/spark/sql/DataFrameStatSuite.scala | 11 +++++++++++
2 files changed, 13 insertions(+), 2 deletions(-)
diff --git a/sql/core/src/main/scala/org/apache/spark/sql/execution/stat/FrequentItems.scala b/sql/core/src/main/scala/org/apache/spark/sql/execution/stat/FrequentItems.scala
index 34bd243d58..b19344f043 100644
--- a/sql/core/src/main/scala/org/apache/spark/sql/execution/stat/FrequentItems.scala
+++ b/sql/core/src/main/scala/org/apache/spark/sql/execution/stat/FrequentItems.scala
@@ -40,7 +40,7 @@ private[sql] object FrequentItems extends Logging {
if (baseMap.size < size) {
baseMap += key -> count
} else {
- val minCount = baseMap.values.min
+ val minCount = if (baseMap.values.isEmpty) 0 else baseMap.values.min
val remainder = count - minCount
if (remainder >= 0) {
baseMap += key -> count // something will get kicked out, so we can add this
@@ -83,7 +83,7 @@ private[sql] object FrequentItems extends Logging {
df: DataFrame,
cols: Seq[String],
support: Double): DataFrame = {
- require(support >= 1e-4, s"support ($support) must be greater than 1e-4.")
+ require(support >= 1e-4 && support <= 1.0, s"Support must be in [1e-4, 1], but got $support.")
val numCols = cols.length
// number of max items to keep counts for
val sizeOfMap = (1 / support).toInt
diff --git a/sql/core/src/test/scala/org/apache/spark/sql/DataFrameStatSuite.scala b/sql/core/src/test/scala/org/apache/spark/sql/DataFrameStatSuite.scala
index ab7733b239..73026c749d 100644
--- a/sql/core/src/test/scala/org/apache/spark/sql/DataFrameStatSuite.scala
+++ b/sql/core/src/test/scala/org/apache/spark/sql/DataFrameStatSuite.scala
@@ -235,6 +235,17 @@ class DataFrameStatSuite extends QueryTest with SharedSQLContext {
assert(items.length === 1)
}
+ test("SPARK-15709: Prevent `UnsupportedOperationException: empty.min` in `freqItems`") {
+ val ds = spark.createDataset(Seq(1, 2, 2, 3, 3, 3))
+
+ intercept[IllegalArgumentException] {
+ ds.stat.freqItems(Seq("value"), 0)
+ }
+ intercept[IllegalArgumentException] {
+ ds.stat.freqItems(Seq("value"), 2)
+ }
+ }
+
test("sampleBy") {
val df = spark.range(0, 100).select((col("id") % 3).as("key"))
val sampled = df.stat.sampleBy("key", Map(0 -> 0.1, 1 -> 0.2), 0L)
--
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